It’s clear to anyone who has been using email for any length of time that spam is a problem. But why is it a problem? After all, snail mail has “spam” as well, but nobody seems to complain too much about that!
It turns out that despite the intentions of the creators of SMTP†, there are in fact a lot of differences between email and snail mail that makes the “spam” problem less relevant to the latter than the former.
First of all, and most obviously, is the issue of cost. It costs money to send snail mail. In Australia, it’s 50c per letter. That’s only very nominal for one person sending one message, but it’s quite prohibitive if you want to send thousands. And in fact, that’s why most snail mail “spam” is hand-delivered by school kids – it’s cheaper to pay a kid $6 an hour, than it is to pay 50c per message. But even if you hand-deliver your snail mail spam, you’ve still got to pay for the paper and printing costs, the designers, etc. Email spam is free – all you pay for is the bandwidth, and since most spam is sent from botnets, it’s not even your own bandwidth that you’re using.
The second difference is that snail mail spam does not get sent to business addresses. The kid hand delivering the messages knows that nobody will read it if it’s the letterbox of a shop, so they don’t even bother putting in the mailbox. But even if they did, that’s only one person in the whole company that has to deal with it. Email spam is indiscriminate – it goes to everybody’s mailbox. So if you have to spend 30 seconds a day sorting your snail mail spam from the real stuff, multiply that by 30 seconds a day sorting email spam by the number of people in your company, and that becomes a lot of wasted time!
A third difference that is somewhat related to the first is that if you’re going to spend several thousand dollars to send out snail mail spam, you need to know that you’re actually going to get a pretty good return. So you hire designers and artist to build you a nice catalogue (or whatever), you figure out your demographics and the locations they live, and you target them. This means that many people actually do read your message. Spam, being free, is usually just typed up by some guy with only a basic grasp of the English language, no design skills, and is just sent to as many addresses as possible. So 99.999% of spam messages are not read.
Fourthly, there are many laws governing the sending of snail mail spam. Because the delivery is necessarily limited to just a single country, law can be made an enforced easily. Email spam is sent to all countries, indiscriminately, so it’s not possible to actually enforce any laws (because which country’s law do you enforce? Remember it’s also quite difficult to pinpoint the origin of the email as well).
Finally, and I don’t consider this as big a threat as you might, but email spam can contain viruses, snail mail spam cannot.
So you can see that all these differences boil down to basically one of two things: 1. spam is free, and 2. spam is indiscriminate. Any “real” solution to the probably would have to address of these two problems, I believe – make them a non-issue and email spam would be as big a deal as snail mail spam (that is, not much).
† See, SMTP as a protocol works a lot like snail mail. You write the address of the person you’re sending to on the envelope (which is equivalent to the RCPT TO command), scrawl your return-address on the back of the envelope (which is not required – if there’s a problem and you don’t give a return address, you just don’t get notified of the problem. This is equivalent to the MAIL FROM command – if you specify a bogus address, it doesn’t matter, you just don’t get notified of failures). What you specify in the actual letter (i.e. the DATA command) is irrelevant to the successful delivery of the message (so you can have something totally different in the To: and From: for example).